Suspension systems that adjust the height, or ground clearance, of a vehicle have been known for some time. A suspension assembly that adjusts the track width of a vehicle, however, is unknown to the applicants. A fully interchangeable suspension assembly, that is, one that can be readily exchanged in a left-to-right, front-to-back, steerable-to-nonsteerable, and driven-to-nondriven manner, is also unknown to the applicants, as is a dual control arm suspension that has at least 120 degrees of angular travel and that swings into an upright stowed position within a relatively shallow recess.